<body>  <h2>基本选择器</h2>  <div id="title"></div>  <div class="context"></div>  <div class="context"></div>  <p>一段描述……</p>  <script src="jquery-1.12.4.min.js"></script>  <script>    console.log($('#title'));    console.log($('.context'));    console.log($('h2,p'));  </script></body>